Announcing the newest version of the Raptor 140! Its main objective is to fly over 120km(75mi) at 115kph(71mph) and send signals (including video!) over 3km(1.9mi). It should be ready to fly early February 2014. Anything you see in my design that I should reconsider?
Estimated Raptor 140c Stats:
Weight: 2100g (4.6lbs)
Max Flight Time: 100min (1hr, 40min)
Max Range: 120km (75mi)
Stall Speed: 35kph (22mph)
Cruise Speed: 115kph (71mph)
Max Speed: 145kph (90mph)
Radio Range: 3.5km (2.2mi)
Energy Carried: 289wh (20,100mAh at 14.4v)
Drive Power: 850w
Meters per Watt/Hour: 450
Features of the 140c (improvements over 140b in parentheses):
Airframe:
-MyGeekShow's Raptor 140: 140cm Wing Span
-CG at 26cm from nose (very, very balanced, almost zero reflex)
-EPP foam construction
-5mil Laminate covering
-Aluminum Motor Mount
-Additional laminate to strengthen leading edge (allow for rougher landings)
-6.4m (21ft) of carbon fiber (had 4.5m) (add additional rigidity)
-5cm x 48.5 elevons for low drag control surfaces
-Laminate elevon hinges (more strength and durability than packing tape)
-14cm winglets for visibility and lift improvement
-Integrated steel launch hook, closer to CG (better bungee launches)
-Parachute ring (allow parachute recover system)
-Velcro battery retainers
-PET plastic battery covers
-Plastic flight controller cover
-Precipitation 100% sealed (can fly in rain)
Flight Systems:
-433mhz EZUHF radio system (500%+ radio range improvement)
-32g servo (additional pull strength and durability)
-1250kv motor, was 1450kv (slower rotation as it is switching to 14.4v from 11.1v)
-24 3.6v Li-Ion 3.3Ah cells in 4S6P, aka 289watt/hours (20.3Ah at 14.4v) Raptor 140B carried 111watt/hours
-10x6 carbon fiber folding prop (140B had a 10x7 due to higher kv motor)
-4.7cm aluminum prop hub
-Wiring lanes in airframe (improved wire management)
-4 Ferrite Filters (cleaner transmissions and reduced interference)
Avionics:
-1080 HD Mobius camera (was 720 808 #16)
-FPV tx 1.3Ghz 400mw
-APM2.6 flight controller
-3DR Current Sensor
-3DR uBlox GPS with compass
-1w 900mhz 900RDF telemetry (had 0.1w telem)
-FAA style lighting (improved visibility)
-3A BEC (provides power to telemetry, camera, etc)
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Learn More:
Raptor Details: http://www.mygeekshow.com/theairplanes/Raptor140.html
USA Trip Details: http://www.mygeekshow.com/usatrip/
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Filmed, Edited, Produced and Published by Trent in Arkansas, USA
Comments
Hey Trent,
Do you think you could share some details about the airfoil you used?
Thanks,
Madhu.
F5, F5 :)
Wow! That was some fast responses :)
Gustav: Maybe we're talking semantics, but what I mean is if want x watts, and I increase volts, then I can decrease amps.
In terms of electromagnetism, one watt is the rate at which work is done when one ampere (A) of current flows through an electrical potential difference of one volt (V).
Sorry, didn't mean to beat a dead horse. Three responses in the span of a minute.
Gustav, by "maintaining the same watts" with an increase in voltage, he is implying a change in motor and/or prop.
Gustav, you're wrong.
All else being equal, the motor needs to deliver a certain power to achieve a flight performance. That means a fixed number of watts. Watts = Volts x Amps. So it takes less amps to make a given power at higher volts.
What you say is only true if you were to run the exact same motor at full throttle constantly. But then you'd be producing way more power, and the airplane would be flying faster.
Gustav, we went from 3S 5400mah 1250kv motor 9x6 prop to 6S 2600mAh 700kv motor 9x6 prop.
Current in steady cruise went from 8.6A to 3.7A, higher voltage -> less than half the current
Wrong.
Your speed controller and motor effectively is a DC load.
The higher the voltage, the higher the current.
I've had this argument over and over with visitors to the LHS.
Trung: Empirical data : ) Just based on amps and prop pitch and all that I've seen from the 120, 140a, 140b.
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